South Korean President Moon Jae-in says North Korea should take bold steps towards denuclearisation, such as abandoning long-range missiles, to extract US concessions amid a prolonged stalemate in their nuclear negotiations.
Moon Jae-in also said the North would have to seek a compromise in a second summit between North Korean leader Kim Jong-un and US President Donald Trump, which he said could be imminent, in order to resolve the impasse.
Pyongyang and Washington have been struggling to find a breakthrough despite a pledge by Kim at his landmark summit with US President Donald Trump in Singapore in June to work towards denuclearisation.
Pyongyang has demanded Washington lift sanctions, imposed because of its nuclear and missile tests, and declare an official end to the 1950-53 Korean War.
Those demands were in response to Pyongyang's initial, unilateral steps toward denuclearisation that included dismantling its only known nuclear testing site and a key missile engine facility.
Moon said North Korea should take more concrete steps, such as abandoning its intercontinental and intermediate-range ballistic missiles and dismantling weapons production lines and other nuclear complexes, to secure US concessions such as sanctions relief.
He said reducing US military commitments, such as a withdrawal of troops or strategic assets from the region, would be an unlikely option for Washington.
"The second summit would be a venue where they settle on terms of what specific measures North Korea will take and how those moves will be reciprocated by the United States," Moon told a news conference on Thursday.
"But US forces in South Korea or strategic assets in places like Guam and Japan are not linked with North Korea alone, as they exist for the stability and peace of the entire Northeast Asia," he said.
Kim renewed his resolve to meet Trump again during his meeting with Chinese President Xi Jinping in Beijing this week. Moon said Kim's latest trip to Beijing signalled that a second Trump summit was imminent.
Another US-North Korea summit would also expedite an unprecedented visit by Kim to Seoul, planned for last year but delayed amid the nuclear stand-off, Moon said.
China's official Xinhua news agency also said Pyongyang's "legitimate concerns" must be taken seriously in order to achieve a comprehensive resolution on the Korean peninsula.
Xinhua quoted Xi as saying he hoped that North Korea and the United States could meet each other half way and that the international community expected peaceful negotiations.
